In recent years, as a material to cover a light-emitting element, a TeO2 type glass containing TeO2 as the main composition, is proposed. However, the TeO2 type glass employed as the covering material, has a poor transmittance at a wavelength shorter than 400 nm, and is not suitable as a sealing material for a short wavelength (365 to 405 nm) LED (UV-LED).
Here, there is a document (Patent Document 1) which discloses use of a P2O5—ZnO type glass as the sealing material for a short wavelength LED.
Patent Document 1: WO2004/082036